I just started learning how to use a soroban this week. If you're looking for a soroban training app, this is the one. Your training is very customizable for your own needs (several different practice options and difficulties are provided), and a record of your times and your best time are recorded, along with the time and date. If you own your own soroban, this is still a great app; in the options you can change the mode to practice with a real soroban (it simply displays the problem, and when you are done you can check your answer). The ads aren't too intrusive, especially for an app as well designed as this one: there are banner ads and the occasional pop-up ad. I myself purchased the ad removal to support the developer despite the ads not being excessive. Bottom line: Although I am very new to the soroban, I can't see myself needing anything other than this app to practice.